# -*- coding: utf-8 -*-

class _const(object):
    class ConstError(PermissionError): pass
    def __setattr__(self, name, value):
        if name in self.__dict__.keys():
            raise self.ConstError( "Can't rebind const(%s)" % name)
        self.__dict__[name] = value


    def __delattr__(self, name):
        if name in self.__dict__:
            raise self.ConstError("Can't unbind const(%s)" % name)
        raise NameError(name)


import sys
sys.modules[__name__] = _const()

